3,945 research outputs found
Fasting and nutrient-stimulated plasma peptide-YY levels are elevated in critical illness and associated with feed intolerance: an observational, controlled study
INTRODUCTION: Delayed gastric emptying and feed intolerance occur frequently in the critically ill. In these patients, gastric motor responses to nutrients are disturbed. Peptide YY (PYY) slows gastric emptying. The aim of this study was to determine fasting and nutrient-stimulated plasma PYY concentrations and their relationship to cholecystokinin (CCK) in critically ill patients. METHODS: Studies were performed in 19 unselected mechanically ventilated critically ill patients (12 males; 48 ± 7 years old) in a randomised, single-blind fashion. Subjects received a 60-minute duodenal infusion of Ensure(® )at either 1 or 2 kcal/minute. Blood samples were collected at baseline and at 20, 40, 60, and 180 minutes following commencement of the nutrient infusion for the measurement of plasma PYY and CCK concentrations (using radioimmunoassay). Patient data were compared to 24 healthy subjects (17 males; 43 ± 2 years old). RESULTS: Fasting PYY concentration was higher in patients (P < 0.05), particularly in those with feed intolerance (P < 0.05). Plasma PYY concentrations were higher in patients during nutrient infusion (area under the curve [AUC] at 1 kcal/minute: 2,265 ± 718 versus 1,125 ± 138 pmol/l.min, P < 0.05; at 2 kcal/minute: 2,276 ± 303 versus 1,378 ± 210 pmol/l.min, P = 0.01) compared to healthy subjects. The magnitude of PYY elevation was greater in patients during the 1 kcal/minute infusion (AUC: 441 ± 153 versus 186 ± 58 pmol/l.min, P < 0.05), but not the 2 kcal/minute infusion. Fasting and nutrient-stimulated plasma CCK concentrations were higher in patients (P < 0.05). There was a relationship between plasma PYY and CCK concentrations during fasting (r = 0.52, P < 0.05) and nutrient infusion (r = 0.98, P < 0.0001). CONCLUSION: In critical illness, both fasting and nutrient-stimulated plasma PYY concentrations are elevated, particularly in patients with feed intolerance, in conjunction with increased CCK concentrations
Carbonization and H3PO4 activation of fern Dicranopteris linearis and electrochemical properties for electric double layer capacitor electrode
Today, the world’s climate change is a growing problem, plant carbon sequestration is one of the effective ways to mitigate climate change by reducing greenhouse gases, mostly carbon gases. Dicranopteris linearis (D. linearis), a common fern species in the tropic or subtropic ecoregions, has been recently recognized as a potential feedstock to produce highly porous biochar. This study aims to enhance the specific surface area (SSA) and pore volumes of biochars derived from the D. linearis by H3PO4 activation and examine electrical properties of the activated biochars and their possible usage for the electric double-layer capacitor (EDLC) electrode. The treated raw fern was activated with H3PO4 85% by the three different mixing ratios 1:0, 1:1, and 1:3 (w/w) and then pyrolysis under N2 flow maintained at 500 °C for 1 h. The performance as the electrode for an EDLC was evaluated in 1 mol L−1 H2SO4 solution for the H3PO4-activated samples. The SSA and pore volumes were drastically increased after activation. The maximum SSA and pore volume were 1212 m2 g−1 and 1.43 cm3 g−1, respectively for the biochar activated at 400 °C with a weight mixing ratio 1:3 (w/w) between the fern and H3PO4 acid while these values of the biochar at 400 °C were 12 m2 g−1 and 0.02 cm3 g−1, respectively. The biochar activated at 600 °C with the mixing ratio 1:1 (w/w) showed the maximum capacitance value, ca. 108 F g−1 at 1 mV s−1. The activation using H3PO4 showed a positive tendency to enhance electrochemical properties and it could be a premise toward a higher performance of EDLC from the D. linearis derived activated biochar
The relationship between gastric emptying, plasma cholecystokinin, and peptide YY in critically ill patients
© 2007 Nguyen et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background Cholecystokinin (CCK) and peptide YY (PYY) are released in response to intestinal nutrients and play an important physiological role in regulation of gastric emptying (GE). Plasma CCK and PYY concentrations are elevated in critically ill patients, particularly in those with a history of feed intolerance. This study aimed to evaluate the relationship between CCK and PYY concentrations and GE in critical illness. Methods GE of 100 mL of Ensure® meal (106 kcal, 21% fat) was measured using a 13C-octanoate breath test in 39 mechanically ventilated, critically ill patients (24 males; 55.8 ± 2.7 years old). Breath samples for 13CO2 levels were collected over the course of 4 hours, and the GE coefficient (GEC) (normal = 3.2 to 3.8) was calculated. Measurements of plasma CCK, PYY, and glucose concentrations were obtained immediately before and at 60 and 120 minutes after administration of Ensure. Results GE was delayed in 64% (25/39) of the patients. Baseline plasma CCK (8.5 ± 1.0 versus 6.1 ± 0.4 pmol/L; P = 0.045) and PYY (22.8 ± 2.2 versus 15.6 ± 1.3 pmol/L; P = 0.03) concentrations were higher in patients with delayed GE and were inversely correlated with GEC (CCK: r = -0.33, P = 0.04, and PYY: r = -0.36, P = 0.02). After gastric Ensure, while both plasma CCK (P = 0.03) and PYY (P = 0.02) concentrations were higher in patients with delayed GE, there was a direct relationship between the rise in plasma CCK (r = 0.40, P = 0.01) and PYY (r = 0.42, P < 0.01) from baseline at 60 minutes after the meal and the GEC. Conclusion In critical illness, there is a complex interaction between plasma CCK, PYY, and GE. Whilst plasma CCK and PYY correlated moderately with impaired GE, the pathogenetic role of these gut hormones in delayed GE requires further evaluation with specific antagonists.Nam Q Nguyen, Robert J Fraser, Laura K Bryant, Marianne J Chapman, Judith Wishart, Richard H Holloway, Ross Butler, and Michael Horowit
Generation of three-dimensional multiple spheroid model of olfactory ensheathing cells using floating liquid marbles
We describe a novel protocol for three-dimensional culturing of olfactory ensheathing cells (OECs), which can be used to understand how OECs interact with other cells in three dimensions. Transplantation of OECs is being trialled for repair of the paralysed spinal cord, with promising but variable results and thus the therapy needs improving. To date, studies of OEC behaviour in a
multicellular environment have been hampered by the lack of suitable three-dimensional cell culture models. Here, we exploit the floating liquid marble, a liquid droplet coated with hydrophobic powder
and placed on a liquid bath. The presence of the liquid bath increases the humidity and minimises the effect of evaporation. Floating liquid marbles allow the OECs to freely associate and interact to produce OEC spheroids with uniform shapes and sizes. In contrast, a sessile liquid marble on a solid surface suffers from evaporation and the cells aggregate with irregular shapes. We used floating liquid marbles to co-culture OECs with Schwann cells and astrocytes which formed natural structures without the confines of gels or bounding layers. This protocol can be used to determine how OECs and other cell types associate and interact while forming complex cell structuresJSJ was funded by a grant from the Perry Cross Spinal Research Foundation; NTN was funded from Griffith University through a start-up grant and a grant from the Griffith University Research Infrastructure
Program; JAK was funded by an Australian Research Council Discovery Grant DP150104495; JT was funded by an Eskitis Institute scholarship; CO was funded by a Griffith Sciences scholarship; RV was funded by a Griffith University International Postgraduate Research Scholarshi
Conclusive experimental demonstration of one-way Einstein-Podolsky-Rosen steering
Einstein-Podolsky-Rosen steering is a quantum phenomenon wherein one party
influences, or steers, the state of a distant party's particle beyond what
could be achieved with a separable state, by making measurements on one half of
an entangled state. This type of quantum nonlocality stands out through its
asymmetric setting, and even allows for cases where one party can steer the
other, but where the reverse is not true. A series of experiments have
demonstrated one-way steering in the past, but all were based on significant
limiting assumptions. These consisted either of restrictions on the type of
allowed measurements, or of assumptions about the quantum state at hand, by
mapping to a specific family of states and analysing the ideal target state
rather than the real experimental state. Here, we present the first
experimental demonstration of one-way steering free of such assumptions. We
achieve this using a new sufficient condition for non-steerability, and,
although not required by our analysis, using a novel source of extremely
high-quality photonic Werner states.Comment: Supplemental Material included in the documen
Transversely-intersecting D-branes at finite temperature and chiral phase transition
We consider Sakai-Sugimoto like models consisting of Dq-Dp-anti-Dp-branes
where flavor Dp and anti-Dp-branes transversely intersect color Dq-branes along
two (r+1)-dimensional subspaces. For some values of p and q, the theory of
intersections dynamically breaks non-Abelian chiral symmetry which is
holographically realized as a smooth connection of the flavor branes at some
point in the bulk of the geometry created by Dq-branes. We analyze the system
at finite temperature and map out different phases of the theory representing
chiral symmetry breaking and restoration. For q<5 we find that, unlike the
zero-temperature case, there exist two branches of smoothly-connected solutions
for the flavor branes, one getting very close to the horizon of the background
and the other staying farther away from it. At low temperatures, the solution
which stays farther away from the horizon determines the vacuum. For background
D5 and D6-branes we find that the flavor branes, like the zero temperature
case, show subtle behavior whose dual gauge theory interpretation is not clear.
We conclude with some comments on how chiral phase transition in these models
can be seen from their open string tachyon dynamics.Comment: 35 pages, 7 figures, minor changes, published versio
Cross Section and Transverse Single-Spin Asymmetry of Mesons in Collisions at GeV at Forward Rapidity
We present a measurement of the cross section and transverse single-spin
asymmetry () for mesons at large pseudorapidity from
~GeV collisions. The measured cross section for
~GeV/ and is well described by a
next-to-leading-order perturbative-quantum-chromodynamics calculation. The
asymmetries have been measured as a function of Feynman- () from
, as well as transverse momentum () from
~GeV/. The asymmetry averaged over positive is
. The results are consistent with prior
transverse single-spin measurements of forward and mesons at
various energies in overlapping ranges. Comparison of different particle
species can help to determine the origin of the large observed asymmetries in
collisions.Comment: 484 authors, 13 pages, 11 figures, 4 tables, 2008 data. v2 is version
accepted by Phys. Rev. D. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (or will be)publicly
available at http://www.phenix.bnl.gov/papers.htm
Upsilon (1S+2S+3S) production in d+Au and p+p collisions at sqrt(s_NN)=200 GeV and cold-nuclear matter effects
The three Upsilon states, Upsilon(1S+2S+3S), are measured in d+Au and p+p
collisions at sqrt(s_NN)=200 GeV and rapidities 1.2<|y|<2.2 by the PHENIX
experiment at the Relativistic Heavy-Ion Collider. Cross sections for the
inclusive Upsilon(1S+2S+3S) production are obtained. The inclusive yields per
binary collision for d+Au collisions relative to those in p+p collisions
(R_dAu) are found to be 0.62 +/- 0.26 (stat) +/- 0.13 (syst) in the gold-going
direction and 0.91 +/- 0.33 (stat) +/- 0.16 (syst) in the deuteron-going
direction. The measured results are compared to a nuclear-shadowing model,
EPS09 [JHEP 04, 065 (2009)], combined with a final-state breakup cross section,
sigma_br, and compared to lower energy p+A results. We also compare the results
to the PHENIX J/psi results [Phys. Rev. Lett. 107, 142301 (2011)]. The rapidity
dependence of the observed Upsilon suppression is consistent with lower energy
p+A measurements.Comment: 495 authors, 11 pages, 9 figures, 5 tables. Submitted to Phys. Rev.
C. Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
meson production in Au collisions at GeV
The PHENIX experiment has measured meson production in Au
collisions at GeV using the dimuon and dielectron decay
channels. The meson is measured in the forward (backward) -going
(Au-going) direction, () in the transverse-momentum
() range from 1--7 GeV/, and at midrapidity in the
range below 7 GeV/. The meson invariant yields and
nuclear-modification factors as a function of , rapidity, and centrality
are reported. An enhancement of meson production is observed in the
Au-going direction, while suppression is seen in the -going direction, and
no modification is observed at midrapidity relative to the yield in
collisions scaled by the number of binary collisions. Similar behavior was
previously observed for inclusive charged hadrons and open heavy flavor
indicating similar cold-nuclear-matter effects.Comment: 484 authors, 16 pages, 12 figures, 6 tables. v1 is the version
accepted for publication in Phys. Rev. C. Data tables for the points plotted
in the figures are given in the paper itsel
Measurement of long-range angular correlation and quadrupole anisotropy of pions and (anti)protons in central Au collisions at =200 GeV
We present azimuthal angular correlations between charged hadrons and energy
deposited in calorimeter towers in central Au and minimum bias
collisions at GeV. The charged hadron is measured at
midrapidity , and the energy is measured at large rapidity
(, Au-going direction). An enhanced near-side angular
correlation across 2.75 is observed in Au collisions.
Using the event plane method applied to the Au-going energy distribution, we
extract the anisotropy strength for inclusive charged hadrons at
midrapidity up to GeV/. We also present the measurement of
for identified and (anti)protons in central Au collisions,
and observe a mass-ordering pattern similar to that seen in heavy ion
collisions. These results are compared with viscous hydrodynamic calculations
and measurements from Pb at TeV. The magnitude of
the mass-ordering in Au is found to be smaller than that in Pb
collisions, which may indicate smaller radial flow in lower energy Au
collisions.Comment: 424 authors, 8 pages, and 4 figures. v2 is version accepted for
publication in Phys. Rev. Lett. Published version will be at
http://www.phenix.bnl.gov/phenix/WWW/info/pp1/161/ Plain text data tables
will be at http://www.phenix.bnl.gov/papers.htm
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